566 CLXX. NAIADACEJJ. (J. D. Hooker.) \Potamogeton. 



The PANJAB, Thomson. KASHMIR, alt. 5000 ft., Jacquemont, &c.- DISTBIB. 

 widely diffused especially in temp, climates. 



Stem terete. Leaves 2-6 in. j submerged (if present) sessile, long, narrow, and 

 without a limb. Peduncle stout. Drupelets i in. long. 



3. P. oblong-us, Viv. Fl. Ital. 2, t. 13 ; floating leaves long-petioled 

 elliptic or lanceolate thinly coriaceous, submerged narrowly lanceolate, 

 stipules 1 in., peduncle and dense-fld. spike very slender, drupelets 

 minute shortly beaked not keeled. Engl. Bot. t. 2849. P. polygonifolius, 

 Pourr. in Mem. Ac.ad. Toul. iii. (1788), 325 ; SooTc. f. Students 1 Brit. Fl. 

 Ed. 3, 431. P. digynus and P. elegans, Wall. Gat. 5177, 5178. 



NEPAL, Wallich. KHASIA HILLS, alt. 4-5000 ft. J.D.H. $ T.T. SINGAPORE ? 

 Wallich. DISTRIB. Temp, and trop. regions of the old world. 



The more membranous leaves, shorter stipules, very slender peduncle and 

 spike, smaller flowers and minute drupelets not -^ in. long, distinguish this from P. 

 no.ta.ns. 



4. P. javanicus, Hassk. in Verh. NatuurJc. Ver. Ned. Ind. i. (1856), 

 26 ; floating leaves small ovate-oblong or elliptic acute at both ends 

 5-7-nerved longer than their petiole, submerged linear acuminate, stipules 

 |-1 in., peduncle slender, spike lax fld., drupelets ^-orbicular beaked, ribs 

 often toothed or tubercled, beak hooked, Miq. Fl. Ind. Bat. iii. 750. P. 

 tenuicaulis, F. Muell. Fragn. i. 90, 244; BentJi. Fl. Austral, vii. 171. P. 

 parvifolius, Bucken. in Brem. Abhandl. vii. (1880), 32. P. heterophyllus, 

 Ham. in Wall. Gat. 5181. P. hybridus, Mich. ? Herb. Ind. Or. Hf. & T. 



Plains of INDIA ; ascending the Himalaya to 7000 ft., in the N. West, and 

 9000 ft. in Sikkim. KHASIA HILLS, alt. 6000 ft. DISTBIB. Trop. Asia, Africa and 

 Australia. 



Stem very slender. Leaves -i-lj- in. ; blade twice as long as the petiole or longer 

 Spike -J in. ; flowers very small, in interrupted whorls ; peduncle as long or 

 longer. Sepals orbicular-obovate. Drupelets -^ in., turgid, beak stout. 



** Leaves all submerged, ovate oblong or broadly linear, translucent. 



5. P. perfoliatus, Linn. Sp. PI. 126 ; stem stout, leaves amplexicaul 

 ovate-cordate entire 5-9-nerved, peduncle short stout, drupelets hardly 

 keeled shortly beaked. Kunih Enum. iii. 133; Reichb. Ic. Fl. Germ. 

 vii. t. 29 ; Boiss. Fl. Orient, v. 17 ; Dalz. & Gibs. Bomb. Fl. 248. 



WESTERN HIMALAYA ; from Kashmir to Kumaon, alt. 4-8000 ft. WESTERN 

 TIBET, alt. 8-14,000 ft. DISTRIB. N. temp, regions, Australia. 



Stem terete, dichotomous. -Leaves 1-4 in., margins scaberulous, upper opposite; 

 stipules small, caducous. Peduncle stout, not thickened upwards. Spike dense-fld. 

 Sepals long-clawed. Drupelets ^ in., compressed, beak straight. 



6. Pi crispus, Linn. Sp. PI. 126; stem slender, leaves semiamplexi- 

 caul linear or linear-oblong crisped serrulate 3-nerved, peduncle curved 

 tapering upwards, spike few-fld., drupelets obliquely ovoid long-beaked. 

 KuntTi Enum. iii. 133 ; Reichb. Ic. Fl. Germ. vii. t. 29, 30 ; Boiss. Fl. Orient. 

 v. 17. P. tuberosus, Roxb. Fl. Ind. i. 472 ; Wall. Cat. 5174 ; Grah. Cat. 

 Bomb. Fl. 200; Dalz 8f Gibs. Bomb. Fl. 248. P. crenulatus, Don Prodr. 

 22. 



PLAINS of INDIA and TEMPERATE HIMALAYA; from Kashmir to Bhotan, alt. 

 4-6000 ft. MUNNIPORE, Watt. DISTRIB. N. and S. temp, and subtrop. regions. 



Stem dichotomous, compressed. Leaves 1-3 in., alternate and narrowed at the 

 base, or opposite and amplexicaul, tip rounded ; stipules small, caducous. Peduncle 



